It is our intent to study the nature of the pulmonary vascular smooth muscle cell (SMC). Culturing of the SMC will be attempted from the pulmonary arteries of rabbits and normal and spontaneously hypertensive (SHR) rats. The ultrastructure of the cells will be evaluated as a function of time in culture, number of subcultures, and hypoxia. These data will be correlated to connective tissue synthesis, focusing on the proteins, collagen and elastin. Also included in these studies are the effects of vasoactive agents, such as prostaglandins and angiotension, on cell growth and connective tissue synthesis and the response to the SMC to the hypoxic state. Our major aim is to prepare stretchable artificial biomembranes which are capable of supporting cultured cells and, when required, will tolerate stretch and/or pressure without breaking. Smooth muscle cells grown on such membranes will be subjected to stretch and/or pressure; ultrastructural, connective tissue and prostaglandin changes, if any, will be monitored. It is hoped that by having available the pulmonary SMC and the development of stretchable biomembranes which can support them, we can simulate certain of the stress effects the pulmonary vascular smooth muscle experiences in pulmonary hypertension.